Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/21/2014
Publication Date: 1/30/2014
Publication URL: http://handle.nal.usda.gov/10113/58959
Citation: Dinh, H., Hong, Y.H., Lillehoj, H.S. 2014. Modulation of microRNAs in two genetically disparate chicken lines showing different necrotic enteritis disease susceptibility. Veterinary Immunology and Immunopathology. 159(1-2):74-82. doi: 10.1016/j.vetimm.2014.02.003. Interpretive Summary: Necrotic enteritis (NE) is an acute disease caused by the bacterium Clostridium (C.) perfringens that can result in weight loss, a depressed appetite, and sudden death. Because of the risk of transmission to humans through the food chain, C. perfringens poses food safety hazards to humans. Although in-feed “growth promoter” antibiotics (AGPs) has controlled NE effectively, NE has reemerged as a significant problem in many countries where the governmental regulation of AGP usage in animal production. A specialized subset of ribonucleic acid (RNA) molecules, known to regulate the production of protein from specific genes, have been suggested to play a critical role in the regulation of a diverse number of functions within biological processes of an animal, such as immune response to disease causing organisms. In this study, ARS scientists teamed up with other scientists at a Korean university to study this RNA subset in chickens that are susceptible or resistant to NE. The results showed that significant changes in the type and quantity of the RNA subset was associated with NE disease and further studies will be necessary to obtain detailed immune mechanisms associated with NE. Understanding the mechanisms within the cell and their reliance on genes controlled by distinct members of the RNA subset in the regulation of host response to NE-causing organisms will facilitate the development of a logical approach to immunological control of NE. This study provide a groundwork upon which future studies of the function of these RNA subset and their target genes in the host that will enhance our understanding of molecular mechanisms controlling host-pathogen interaction in NE.
Technical Abstract: MicroRNAs (miRNA) play a critical role in post-transcriptional regulation by influencing the 3'-UTR of target genes. Using two inbred White Leghorn chicken lines, line 6.3 and line 7.2 showing Marek’s disease-resistant and -susceptible phenotypes, respectively, we used small RNA high-throughput sequencing (HTS) to investigate whether miRNAs are differently expressed in these two chicken lines after inducing necrotic enteritis (NE). The 12 miRNAs, selected from the most down-regulated or up-regulated miRNAs following NE induction, were confirmed by their expression via real-time PCR. Among these miRNAs, gga-miR-215, miR-217, miR-194, miR-200a, miR-200b, miR-216a, miR-216b, and miR-429 in line 7.2, and miR-1782 and miR-499 in line 6.3 were highly expressed in intestinal intraepithelial lymphocytes (IELs). Notably, four out of six target genes, CXCR5, BCL2, GJA1, and TCF12 were differentially expressed between line 6.3 and line 7.2, and showed suppression in the susceptible chicken line. Their expression levels were conversely correlated with those of miRNA obtained from both HTS and quantitative real-time PCR. These results suggest that some miRNAs are differentially altered in response to NE and they modulate the expression of their target genes in the two inbred lines. Collectively, HTS analysis of intestinal IEL miRNAs from NE-afflicted inbred chickens showing different disease phenotypes led to the identification of host immunity genes regulated by miRNA. Future studies of the function of these miRNAs and their target genes in the host will lead to an enhanced understanding of molecular mechanisms controlling host-pathogen interaction in NE.